Microservices Patterns
With examples in Java
Chris Richardson
  • MEAP began February 2017
  • Publication in October 2018 (estimated)
  • ISBN 9781617294549
  • 477 pages (estimated)
  • printed in black & white

As a senior software engineer working on a very large learning management system I've found Microservices Patterns and your website (http://microservices.io/) to be invaluable in modernizing our architecture...

John I. McSwain, III

The monolithic architecture works well for small, simple applications. However, successful applications have a habit of growing. Eventually the development team ends up in what is known as monolithic hell. All aspects of software development and deployment become painfully slow. The solution is to adopt the microservice architecture, which structures an application as a services, organized around business capabilities. This architecture accelerates software development and enables continuous delivery and deployment of complex software applications.

Microservices Patterns teaches enterprise developers and architects how to build applications with the microservice architecture. Rather than simply advocating for the use the microservices architecture, this clearly-written guide takes a balanced, pragmatic approach. You'll discover that the microservices architecture is not a silver bullet and has both benefits and drawbacks. Along the way, you'll learn a pattern language that will enable you to solve the issues that arise when using the microservices architecture. This book also teaches you how to refactor a monolithic application to a microservices architecture.

Table of Contents detailed table of contents

1. Escaping monolithic hell

1.1. The slow march towards monolithic hell

1.1.1. The architecture of the FTGO application

1.1.2. The benefits of the monolithic architecture

1.1.3. Living in monolithic hell

1.2. Why this book is relevant to you

1.3. What you’ll learn in this book

1.4. The microservice architecture to the rescue

1.4.1. Scale cube and microservices

1.4.2. Microservices as a form of modularity

1.4.3. Each service has its own database

1.4.4. The FTGO microservice architecture

1.4.5. Isn’t the microservice architecture the same as SOA?

1.5. Benefits and drawbacks of the microservice architecture

1.5.1. Benefits of the microservice architecture

1.5.2. The drawbacks of the microservice architecture

1.6. The microservice architecture pattern language

1.6.1. Microservices are not a silver bullet

1.6.2. What is a pattern and a pattern language?

1.6.3. Overview of the microservice architecture pattern language

1.7. Beyond microservices: process and organization

1.7.1. Software development and delivery organization

1.7.2. Software development and delivery process

1.7.3. The human side of adopting microservices

1.8. Summary

2. Decomposition strategies

2.1. What is the microservice architecture exactly?

2.1.1. What is software architecture and why it matters

2.1.2. Overview of architectural styles

2.1.3. The microservice architecture is an architectural style

2.2. Defining an application’s microservice architecture

2.2.1. Identifying the system operations

2.2.2. Defining services by applying the Decompose by business capability pattern

2.2.3. Defining services by applying the Decompose by sub-domain pattern

2.2.4. Decomposition guidelines

2.2.5. Obstacles to decomposing an application into services

2.2.6. Defining service APIs

2.3. Summary

3. Inter-process communication in a microservice architecture

3.1. Overview of inter-process communication in a microservice architecture

3.1.1. Interaction styles

3.1.2. Defining APIs in a microservice architecture

3.1.3. Evolving APIs

3.1.4. Message formats

3.2. Communicating using the synchronous Remote procedure invocation pattern

3.2.1. Using REST

3.2.2. Using gRPC

3.2.3. Handling partial failure using the Circuit Breaker pattern

3.2.4. Using service discovery

3.3. Communicating using the asynchronous Messaging pattern

3.3.1. Overview of messaging

3.3.2. Implementing the interaction styles using messaging

3.3.3. Creating an API specification for a messaging-based service API

3.3.4. Using a message broker

3.3.5. Competing receivers and message ordering

3.3.6. Handling duplicate messages

3.3.7. Transactional messaging

3.3.8. Libraries and frameworks for messaging

3.4. Using asynchronous messaging to improve availability

3.4.1. Synchronous communication reduces availability

3.4.2. Eliminating synchronous interaction

3.5. Summary

4. Managing transactions with sagas

4.1. Transaction management in a microservice architecture

4.1.1. The need for 'distributed transactions' in a microservice architecture

4.1.2. The trouble with distributed transactions

4.1.3. Using the Saga pattern to maintain data consistency

4.2. Coordinating sagas

4.2.1. Choreography-based sagas

4.2.2. Orchestration-based sagas

4.3. Handling the lack of isolation

4.3.1. Overview of anomalies.

4.3.2. Countermeasures for handling the lack of isolation

4.4. The design of the Order Service and the Create Order Saga

4.4.1. The OrderService class

4.4.2. The implementation of the Create Order Saga

4.4.3. The OrderCommandHandlers class

4.4.4. The OrderServiceConfiguration class

4.5. Summary

5. Designing business logic in a microservice architecture

5.1. Business logic organization patterns

5.1.1. Designing business logic using the Transaction script pattern

5.1.2. Designing business logic using the Domain Model pattern

5.1.3. About Domain Driven Design

5.2. Designing a domain model using the DDD aggregate pattern

5.2.1. The problem with fuzzy boundaries

5.2.2. Aggregates have explicit boundaries

5.2.3. Aggregate rules

5.2.4. Aggregate granularity

5.2.5. Designing business logic with aggregates

5.3. Publishing domain events

5.3.1. Why publish change events?

5.3.2. What is a domain event

5.3.3. Event enrichment

5.3.4. Identifying domain events

5.3.5. Generating and publishing domain events

5.3.6. Consuming domain events

5.4. Kitchen Service business logic

5.4.1. The Ticket aggregate

5.5. The Order Service business logic

5.5.1. The Order Aggregate

5.5.2. The OrderService class

5.6. Summary

6. Developing business logic with event sourcing

6.1. Developing business logic using event sourcing

6.1.1. The trouble with traditional persistence

6.1.2. Overview of event sourcing

6.1.3. Handling concurrent updates using optimistic locking

6.1.4. Event sourcing and publishing events

6.1.5. Using snapshots to improve performance

6.1.6. Idempotent message processing

6.1.7. Evolving domain events

6.1.8. Benefits of event sourcing

6.1.9. Drawbacks of event sourcing

6.2. Implementing an event store

6.2.1. How the Eventuate Local event store works

6.2.2. The Eventuate client framework for Java

6.3. Using sagas and event sourcing together

6.3.1. Implementing choreography-based sagas using event sourcing

6.3.2. Creating an orchestration-based saga

6.3.3. Implementing an event sourcing-based saga participant

6.3.4. Implementing saga orchestrators using event sourcing

6.4. Summary

7. Implementing queries in a microservice architecture

7.1. Querying using the API Composition pattern

7.1.1. The findOrder() query operation

7.1.2. An overview of the API composition pattern

7.1.3. Implementing the findOrder() query operation using the API Composition pattern

7.1.4. API Composition design issues

7.1.5. The benefits and drawbacks of the API composition pattern

7.2. Using the Command Query Responsibility Segregation (CQRS) pattern

7.2.1. Motivations for using CQRS

7.2.2. Overview of CQRS

7.2.3. The benefits of CQRS

7.2.4. The drawbacks of CQRS

7.3. Designing CQRS Views

7.3.1. Choosing a view datastore

7.3.2. Data access module design

7.3.3. Adding and updating CQRS views

7.4. Implementing a CQRS view with AWS DynamoDB

7.4.1. OrderHistoryEventHandlers module

7.4.2. Data modeling and query design with DynamoDB

7.4.3. The OrderHistoryDaoDynamoDb class

7.5. Summary

8. External API patterns

8.1. External API design issues

8.1.1. API design issues for the FTGO mobile client

8.1.2. API design issues for other kinds of clients

8.2. The API gateway pattern

8.2.1. Overview of the API gateway pattern

8.2.2. Benefits and drawbacks of an API gateway

8.2.3. Netflix as an example of an API gateway

8.2.4. API gateway design issues

8.3. Implementing an API gateway

8.3.1. Using an off-the-shelf API gateway product/service

8.3.2. Developing your own API gateway

8.3.3. Implementing an API gateway using GraphQL

8.4. Summary

9. Testing microservices - part 1

9.1. Testing strategies for microservice architectures

9.1.1. Overview of testing

9.1.2. The challenge of testing microservices

9.1.3. The deployment pipeline

9.2. Writing unit tests for a service

9.2.1. Developing unit tests for entities

9.2.2. Writing unit tests for value objects

9.2.3. Developing unit tests for sagas

9.2.4. Writing unit tests for domain services

9.2.5. Developing unit tests for controllers

9.2.6. Writing unit tests for event and message handlers

9.3. Summary

10. Testing microservices - part 2

10.1. Writing integration tests

10.1.1. Persistence integration tests

10.1.2. Integration testing REST-based request/reply style interactions

10.1.3. Integration testing publish/subscribe-style interactions

10.1.4. Integration contract tests for Request/async reply interactions

10.2. Developing component tests

10.2.1. Defining acceptance tests

10.2.2. Writing acceptance tests using Gherkin

10.2.3. Designing component tests

10.2.4. Writing component tests for the FTGO Order Service

10.3. Writing end-to-end tests

10.3.1. Designing end-to-end tests

10.3.2. Writing end-to-end tests

10.3.3. Running the end-to-end tests

10.4. Summary

11. Developing production ready services

11.1. Developing secure services

11.1.1. Overview of security in a traditional monolithic application

11.1.2. Implementing security in a microservice architecture

11.2. Designing configurable services

11.2.1. Using push-based externalized configuration

11.2.2. Using pull-based externalized configuration

11.3. Designing observable services

11.3.1. Using the Health check API pattern

11.3.2. Apply the Log aggregation pattern

11.3.3. Using the Distributed tracing pattern

11.3.4. Applying the Application metrics patterns

11.3.5. Using the Exception tracking pattern

11.3.6. Applying the Audit logging pattern

11.4. Developing services using the Microservice chassis pattern

11.4.1. Using a microservice chassis

11.4.2. From microservice chassis to service mesh

11.5. Summary

12. Deploying microservices

12.1. Deploying services using the Language-specific packaging format pattern

12.1.1. Benefits of the Service as a language-specific package pattern

12.1.2. Drawbacks of the Service as a language-specific package pattern

12.2. Deploying services using the Service per Virtual machine pattern

12.2.1. The benefits of deploying services as VMs

12.2.2. The drawbacks of deploying services as VMs

12.3. Deploying services using the Service per container pattern

12.3.1. Deploying services using Docker

12.3.2. Benefits of deploying services as containers

12.3.3. Drawbacks of deploying services as containers

12.4. Deploying the FTGO application with Kubernetes

12.4.1. Overview of Kubernetes

12.4.2. Deploying the Restaurant service on Kubernetes

12.4.3. Deploying the API gateway

12.4.4. Zero-downtime deployments

12.4.5. Using a service mesh so separate deployment from release

12.5. Deploying services using the Serverless deployment pattern

12.5.1. Overview of serverless deployment with AWS Lambda

12.5.2. Developing a lambda function

12.5.3. Invoking lambda functions

12.5.4. Benefits of using lambda functions

12.5.5. Drawbacks of using lambda functions

12.6. Deploying a RESTful service using AWS Lambda and AWS Gateway

12.6.1. The design of the AWS Lambda version of the Restaurant Service

12.6.2. Packaging the service as ZIP file

12.6.3. Deploying lambda functions using the Serverless framework

12.7. Summary

13. Refactoring to microservices

13.1. Overview of refactoring to microservices

13.1.1. Why refactor a monolith?

13.1.2. Strangling the monolith

13.2. Strategies for refactoring a monolith to microservices

13.2.1. Implement new features as services

13.2.2. Separate presentation tier from the back end

13.2.3. Extract business capabilities into services

13.3. Designing how the service and the monolith collaborate

13.3.1. Designing the integration glue

13.3.2. Maintaining data consistency across a service and a monolith

13.3.3. Handling authentication and authorization

13.4. Implementing a new feature as a service: handling mis-delivered orders

13.4.1. The design of the Delayed Delivery Service

13.4.2. Designing the integration glue for the Delayed Delivery Service

13.5. Breaking apart the monolith: extracting delivery management

13.5.1. Overview the existing delivery management functionality

13.5.2. Overview of the Delivery Service

13.5.3. Designing the Delivery Service domain model

13.5.4. The design of the Delivery Service integration glue

13.5.5. Changing the FTGO monolith to interact with the Delivery Service

13.6. Summary

What's inside

  • Understanding the microservices architecture
  • When and when not to use the microservices architecture
  • How to develop a microservices architecture for an application
  • Transaction management and querying in a microservices architecture
  • Effective testing strategies for microservices
  • How to refactor a monolithic application into services

About the reader

Readers should be familiar with the basics of enterprise application architecture, design, and implementation.

About the author

Chris Richardson is a developer and architect. He is a Java Champion, a JavaOne rock star and the author of POJOs in Action, which describes how to build enterprise Java applications with frameworks such as Spring and Hibernate. Chris was also the founder of the original CloudFoundry.com, an early Java PaaS for Amazon EC2. Today, he is a recognized thought leader in microservices. Chris is the creator of http://microservices.io , a website describing how to develop and deploy microservices. He provides microservices consulting and training and is working on his third startup http://eventuate.io , an application platform for developing microservices.

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I loved the use of patterns in presenting microservices. It was a novel approach and worked well. As my team is in the process of converting a SOA service over to microservices, the book was incredibly useful.

Trent Whiteley

The definitive guide about microservices and how to adopt them in your development cycle.

Potito Coluccelli